All You Need To Know About L Carnitine HealthKart Amazon.com: L Carnitine 3000 Liquid 3000 mg Carnitine Supplement Zero Calorie Zero Sugar Keto Friendly for Men and Women Great Tasting 31 Servings (Patriot Pop, 16 fl. oz.) : Health & Household Acetyl L Carnitine vs L Carnitine: 4 Key Differences Momentous Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis When to Take L Carnitine for Optimal Training Benefits Transparent Labs L carnitine is a naturally occurring amino acid structure that is made in the human brain, liver, and kidneys. L carnitine plays a critical role in energy production, as it converts fat into energy.